Autohide für FX 4 ???

if (aShow) {
      gNavToolbox.removeAttribute("inFullscreen");
      document.documentElement.removeAttribute("inFullscreen");
    } else {
      gNavToolbox.setAttribute("inFullscreen", true);
      document.documentElement.setAttribute("inFullscreen", true);
    }


    // In tabs-on-top mode, move window controls to the tab bar,
    // and in tabs-on-bottom mode, move them back to the navigation toolbar.
    // When there is a chance the tab bar may be collapsed, put window
    // controls on nav bar.
    var fullscreenflex = document.getElementById("fullscreenflex");
    var fullscreenctls = document.getElementById("window-controls");
    var ctlsOnTabbar = TabsOnTop.enabled &&
                       !gPrefService.getBoolPref("browser.tabs.autoHide");
    if (fullscreenctls.parentNode.id == "nav-bar" && ctlsOnTabbar) {
      document.getElementById("TabsToolbar").appendChild(fullscreenctls);
      // we don't need this space in tabs-on-top mode, so prevent it from
      // being shown
      fullscreenflex.removeAttribute("fullscreencontrol");
    }
    else if (fullscreenctls.parentNode.id == "TabsToolbar" && !ctlsOnTabbar) {
      document.getElementById("nav-bar").appendChild(fullscreenctls);
      fullscreenflex.setAttribute("fullscreencontrol", "true");
    }


    var controls = document.getElementsByAttribute("fullscreencontrol", "true");
    for (var i = 0; i < controls.length; ++i)
      controls[i].hidden = aShow;
  }